docs: def snap_install_requested():
      """ Determine if installing from snaps
  
      If openstack-origin is of the form snap:track/channel[/branch]
      and channel is in SNAPS_CHANNELS return True.
      """
      origin = config('openstack-origin') or ""
      if not origin.startswith('snap:'):
          return False
  
      _src = origin[5:]
      if '/' in _src:
          channel = _src.split('/')[1]
      else:
          # Handle snap:track with no channel
          channel = 'stable'
      return valid_snap_channel(channel)